The pipeline may be a single pipe or a "pipeline cable", consisting of a number of pipes extending inscrew lines in the cable. It may also comprise conduits and cables in a composite cable.
If it is desirable to be able to lay finished pipelines over long distances it is necessary to allow for a longer production time for the pipeline and considerable dimensions of the drum must be expected with a weight of drum and pipeline in the order of 5000 tons or more.
Pipe laying from a drum is at present carried out by the aid of special vessels, smaller pipelines are sometimes laid by the aid of equipment in component packs which are placed on board a lay vessel when required, so that the vessel can be utilized for other tasks when no pipes are to be laid. Larger and longer pipelines require vessels with permanently mounted laying equipment and a drum, which means that the vessel is out of commission while the pipeline is manufactured on land.